I just got the Dead Ringer, and one of its effects is that you cannot cloak on demand.

What I like to do to get behind enemy lines and start backstabbing my way forward is to run screaming medic, in an effort to justify my returning from the other team side.

I know that you can toggle which weapon your disguise is holding (by pressing B), so I was wondering if you could also lower your health in some fashion as to make this tactic seem more believable (screaming for medic when you're at full health is not)

You take on that player's current health, including any overheal, or 100% health if they're dead (this is most noticable when using the YER)

You take on that player's weapon loadout

Exceptions: Bonk! Atomic Punch, Crit-a-Cola, and Mad Milk show as Pistol, Mantreads or Gunboats show as Shotgun, Ali Baba's Wee Booties or Bootlegger show as Grenade Launcher, Chargin' Targe or Splendid Screen show as Stickybomb Launcher, and Jarate, Razorback, or Darwin's Danger Shield show as SMG). The Build Tool, Destruction Tool, Sapper, and Disguise Kit can not be faked at all when disguised as an enemy Engineer or Spy.

If the team you're disguising as does not have a person playing that class:

You take on a random name from that team

You take on a random amount of health

You take on that class's stock weapons.

Note: It takes a few seconds for the game to update what classes players are playing, so it is possible to disguise as a class that has players, but still get a random name, health, and stock weapons. Disguising again will fix this problem. This is most obvious when disguising as your own team in spawn.

You can recharge your fake health via medkits, Medic, or dispensers (this was added earlier this year), but not the Resupply Cabinet.

You can't change it at will. Once you take on a disguise, the disguise health is whatever the enemy has at that time if alive, or a random amount otherwise. The only way to change it is to "replenish" it using whatever healing mechanisms there are (Medics, Dispensers and medkits). Your disguise won't lose health when you take damage either.

You can see enemy health, though, so if you choose to disguise as an enemy who you know has low health, you may be able to take on his low health too and thus make yourself more believable.